#### 2.3.1 Logical Constructionism and Neutral MonismWhen Russell looks at neutral monism, he sees a theory that embodies the spirit of the “supreme maxim in scientific philosophising” (Russell 1914c: 155) in an especially striking way. This maxim is Occam’s Razor: entities are not to be multiplied without necessity. In one of Russell’s formulations it reads: “Wherever possible, substitute constructions out of known entities for inferences to unknown entities” (Russell 1924: 326). Known entities are those that we know directly or noninferentially; unknown entities are ones we accept only on the basis of inferences from known entities. Russell’s maxim encourages us to discover complex structures of known entities that can play the role the inferred entities were supposed to play. Upon substituting these complex structures—the constructions—for the inferred entities, everything continues to work as before. The point of this complicated procedure is primarily epistemic: we are now no longer burdened with the risky inference to the inferred entities, and thus the risk of error is reduced. Strictly speaking, Russell remains agnostic as to the existence of the original entities targeted by the construction. They are neither identified with nor eliminated by the corresponding construction. Still, the constructions make it possible to arrive at a simplified account of what there is that fits our empirical evidence and exhibits various other theoretical virtues such as greater continuity, causal uniformity, and so on. Thus, the resulting metaphysical theory deserves our provisional assent over competing ones to a degree proportional to such non-demonstrative grounds.Neutral monism holds out the alluring promise that such constructions can be found for all of the inferred entities of physics, psychology, and common sense. All of these bodies of knowledge are preserved, but at a hugely reduced epistemic cost. These are the considerations that drive Russell to embrace neutral monism: it is a perfect fit with his longstanding commitment to the program of logical construction. An added benefit of substituting constructions of neutral entities for physical and mental entities is an elegant solution to the mind-body problem.Logical construction is a process of discovery, not of manipulation: to logically construct _x_ s out of _y_ s is to discover that _y_ s, when they manifest a certain type of structure, can play the role of _x_ s. Russell’s constructions of a point in space, an instant in time, a table, and of a belief may illustrate the procedure. (i) A Russian doll is a good model of how Russell (following Whitehead) proposes to construct a point in space. The rough idea is to take “the class of all those objects which, as one would naturally say, contain the point” (Russell 1914a: 117) and to substitute this class of nested objects (the structure of _y_ s) for points in space (the _x_ s). (ii) Experienced instants in time (the _x_ s) are constructed by discovering that the experiences of a person, each of which is extended in time, can overlap each other in ways that converge on an instant. It is> a group of events, all belonging to his experience, and having the following two properties: (1) any two of the events overlap; (2) no event outside the group overlaps with every member of the group. (Russell 1927b: 288) (iii) Rather than viewing a table as the cause of our table sensations, Russell proposes (again just as a first approximation) to view the table as “the set of all those particulars which would naturally be called ‘aspects’ of the table from different points of view” (Russell 1921: 98). (iv) The logical construction that is to take the place of beliefs consists of the following three components:> We have a proposition, consisting of interrelated images, and possibly partly of sensations; (b) we have the feeling of assent, which is presumably a complex sensation demanding analysis; (c) we have a relation, actually subsisting, between the assent and the proposition, such as is expressed by saying that the proposition in question is what is assented to. (Russell 1921: 251) As these examples show, there is no single method of construction, no single type of structure, suitable for different projects of logical construction. The nature of the _x_ s (the targets of construction) and of the _y_ s (the construction materials) guide the search for structures that will work in the case at hand.#### 2.3.2 Known Neutral EntitiesThe initial stock of known entities with which Russell proposes to carry out this grand project of logical construction seems frightfully small and strikingly non-neutral. It consists of his sensations and images—these loom large in Russell 1919, 1921—and his perceptions (percepts)—these play a prominent role in Russell 1927a, 1927b, 1948. Everything else—electrons, apples, galaxies, experiences, and selves, etc.—is in need of logical construction.For an entity to be neutral is to “have neither the hardness and indestructibility of matter, nor the reference to objects which is supposed to characterize the mind” (Russell 1921: 36; cf. 124). Russell never suspected sensations of being material (in this sense). That sensations contain a mental element (in this sense)—that they consist of a mental act of sensing directed at a non-mental object—was, however, a pivotal part of his earlier view. But then his views changed: